The FAA lacks adequate safeguards to properly oversee and respond to complaints about flight test programs that airlines are required to conduct on aircraft that have undergone major repairs or maintenance, the Office of the Inspector General (OIG) has determined.

As a result, the FAA has agreed to an OIG-recommended course of action designed to resolve the problem, the agency said in a letter to the OIG last month.

The finding came after the OIG for the Department of Transportation investigated a complaint filed early last year by the Allied Pilots Association (APA), which represents American pilots, alleging that American was using unqualified pilots for the flight tests and had a culture of suppressing safety complaints.

The FAA official in charge of overseeing the tests lacked objectivity, the OIG said in an audit finding released Tuesday, due to the personal relationships he had developed over the course of 28 years he had spent working with American. For example, the inspector responded to the APA complaint by requesting information from American that could be used to discredit the pilots who made the complaint.

"While the [FAA] has a tool for assessing its relationships with carriers, the tool did not account for these risk factors," the OIG said. "In addition, the agency used a "best guess" method to determine who should respond to APA's written allegations, and ultimately routed the letter back to the target of the complaint for response."

That FAA inspector at issue, who is not named in the report, was eventually reassigned, but not until four months after his supervisor had raised concerns about the Irving, Texas-based inspector's lack of objectivity with local and regional FAA office managers in March 2017.

The OIG issued seven recommended actions that the FAA should take to address this issue and to prevent similar issues from occurring. Included among them are recommendations that FAA conduct an independent review of its oversight of American's flight operations and that the FAA develop a corrective action plan to address shortcomings in the American flight test program.

Auditors also called on the FAA to develop stricter protocols on FAA oversight requirements of flight test operations and better tools for evaluating the objectivity of inspectors.

The FAA will finish implementing all OIG recommendations by June 30, 2019, the agency said.